This invention relates to a circuit configuration for controlling refrigeration circuits for at least two refrigeration areas, more particularly in beverage dispensers with cooling of the CO.sub.2 water supply and of the beverage-concentrate room by means of one of two evaporators that can alternatively be switched into the refrigeration circuit of a condenser through a valve assembly in accordance with the refrigeration requirement measured by sensors, one of the refrigeration circuits having a higher priority for being switched into circuit.
To pressure-load a plurality of refrigeration areas, more particularly two refrigeration areas, it is common practice, e.g. in refrigerator-freezer combination units, to use a refrigeration system having one condenser and one evaporator for each of the refrigeration areas, wherein a valve system switches the evaporator section into the circuit of the condensers, as required. As a rule, compressor-condensers are employed in this connection. Preferably, the evaporators are switched into the circuit of the condenser, as required, in order to achieve maximum efficiency and to minimize the manufacturing effort. If one of the refrigeration areas is to be cooled in particular--e.g., the deep-freeze cabinet in a refrigerator-freezer combination--a priority switching as known from the prior art is carried into effect. Only after this higher-priority refrigeration area has been sufficiently subjected to the refrigeration process will the other refrigeration area be cooled.
In beverage dispensers in which a blended beverage can be provided by mixing carbonated water with beverage concentrates, it is necessary, or at least advisable, to cool the container in which the carbonated water is held in readiness or in which the water is carbonated. The cooler the water, the greater its ability to absorb CO.sub.2 gas. In addition, when mixing a beverage made of a beverage concentrate and carbonated water, the part by volume of the carbonated water is a multiple of the part by volume of the beverage concentrate, so that the temperature of the carbonated water is also a determinant factor for the temperature of the blended beverage.
The cooling of the carbonated water is subject to a natural limit which is fixed by the freezing point of the mixture. To increase the refrigerating capacity, a portion of the carbonated water is stored as ice. The developing layer of ice is evaluated as a criterion for the cold production.
A temperature of the blended beverage above the desired beverage temperature can be the result of the thermal capacity of the non-refrigerated beverage concentrates and of other disturbing factors during mixing and dispensing. Therefore, in order to provide proper storage conditions for the beverage concentrates, it may be necessary also to cool the storage room for the beverage concentrates. On the other hand, it is also desirable to maximize the "cold capacity" by forming a layer of ice as thick as possible as a precautionary measure if a relatively high beverage-dispensing requirement is expected.